Chosen Solution
Dear all, my beloved PowerBook Titanium does not want to power up. Battery is ok as well as power supply. Any idea?
Try looking here: http://support.apple.com/kb/HT1431#faq8 Resetting the PMU might do the trick. I know the ol’ Titanium is sweet, but it also might be time to look at a newer model.
It could be your DC-in board. The best way to test it would be to slide in another battery that has a charge to it… if the computer turns on, it is most likely your DC-in board. You can purchase one here if you are interested: [linked product missing or disabled: IF133-010-1] And you can look at the repair guide here: PowerBook G4 Titanium DVI DC-In Board Replacement
Try taking out your PRAM battery, shown in the remove PMU guide (it’s the big thing marked 616-0114-A) Disconnect the tri color lead from that to the PMU, start up the PowerBook (it should now work), then reconnect that cable and hopefully you should be left with a functioning PowerBook !
